Method for estimating a service interval for replacing an aqueous liquid filtration device in a motor vehicle

Abstract

A method for evaluating a service interval for replacing a filter of a system for extracting an aqueous liquid from a motor vehicle tank in response to the risk of progressive clogging of said filter from use. A compound clogging risk decision value (K) is generated (320) on the basis of the sum of a plurality of elementary values (k1, k2, k3, k4) of the clogging risk, each related to a risk criterion depending on the operation of the extraction system since commissioning of the filter. The compound clogging risk decision value is compared (340) to a threshold value, and an alert to replace the filtration device is generated (351, 352) if the compound clogging risk value exceeds the threshold value.

1 . A method for evaluating a service interval for replacing a filtration device of an extraction system for extracting an aqueous liquid from a tank of a motor vehicle, in response to a risk of progressive clogging of said filtration device due from use, wherein the method comprises:
 generating a compound clogging risk decision value based on a sum of a plurality of elementary clogging risk values, at least one of said plurality of elementary clogging risk values being linked to a risk criterion, said risk criterion depending on the operation of said extraction system since a commissioning of said filtration device;   comparing of said compound clogging risk decision value with a threshold value; and,   producing an alert for replacing the filtration device if the compound clogging risk value exceeds said threshold value, wherein the plurality of elementary clogging risk values comprises:
 A first value “k 2 ” representing a first clogging risk linked to a volume of liquid pumped by the pump since a last filling of the tank, and 
 a second value “k 3 ” representing a second clogging risk linked to a number of times the tank has been filled since said commissioning of the filtration device. 
   
     
     
         2 . The method of  claim 1 , wherein the extraction system further comprising a pump with a first port connected to the tank via the filtration device and a suction line and a second port connected to an injection device via a delivery line, as well as a return line connected to the delivery line by its first end and opening into the tank by its second end, and the filtration device being arranged on the suction side of the pump, the plurality of elementary clogging risk values comprises a third value “k 1 ” representing the clogging risk linked to the volume of liquid pumped by the pump since commissioning of the filtration device. 
     
     
         3 . The method of  claim 1 , wherein the plurality of elementary clogging risk values comprises a third value “k 4 ” representing the clogging risk linked to the variation in the pressure difference of the liquid on either side of the filtration device. 
     
     
         4 . The method of  claim 1 , wherein the plurality of elementary clogging risk values comprises a third value “k 4 ” representing the clogging risk linked to the variation in the pressure difference of the liquid on either side of the filtration device, and wherein a variation in the pressure difference of the liquid on either side of the filtration device is evaluated as a function of the variation in the pump operating speed at a given operating point. 
     
     
         5 . The method of  claim 1 , wherein the plurality of elementary clogging risk values comprises a third value “k 4 ” representing the clogging risk linked to the variation in the pressure difference of the liquid on either side of the filtration device and wherein a variation in the pressure difference of the liquid on either side of the filtration device is evaluated provided that a determined minimum volume of fluid has been pumped by the pump since the filtration device was commissioned or since a previous evaluation. 
     
     
         6 . The method of  claim 1 , wherein the plurality of elementary clogging risk values comprises a third value “k 4 ” representing the clogging risk linked to the variation in the pressure difference of the liquid on either side of the filtration device, wherein a variation in the pressure difference of the liquid on either side of the filtration device is evaluated provided that a determined minimum volume of fluid has been pumped by the pump since the filtration device was commissioned or since a previous evaluation, and wherein the elementary clogging risk values can be parametrised according to the type of vehicle and/or according to the type of use expected of the vehicle. 
     
     
         7 . The method of  claim 1 , wherein the alert for replacing the filtration device is displayed via a man/machine interface of the vehicle to indicate to a vehicle user the need to replace the filtration device. 
     
     
         8 . The method of  claim 1 , wherein the alert for replacing the filtration device is stored in a non-volatile memory of the vehicle, for indicating to an operator responsible for the maintenance of the vehicle the need to replace the filtration device. 
     
     
         9 . A control unit of a system for extracting a liquid from a tank of a motor vehicle, said control unit comprising means for implementing the method of  claim 1 . 
     
     
         10 . An extraction system for extracting an aqueous liquid from a motor vehicle tank comprising a pump and a filtration device, said pump comprising a first port connected to the tank via the filtration device and a suction line and a second port connected via a discharge line to an injection device of liquid capable of consuming liquid extracted from the tank, said extraction system further comprising a return line connected to the delivery line by a first end and connected to the tank by a second end, as well as a control unit of a system for extracting a liquid from a tank of a motor vehicle, comprising means for implementing the method of  claim 1 , for evaluating a service time interval for replacing the filtration device. 
     
     
         11 . The extraction system of  claim 10 , wherein said extraction system is adapted to extract a liquid additive from a dedicated tank of a motor vehicle and to inject said liquid additive into an exhaust gas treatment system of said motor vehicle. 
     
     
         12 . An exhaust gas treatment system of a motor vehicle comprising the extraction system of  claim 10 , wherein said extraction system is adapted to extract a liquid additive from a dedicated tank of a motor vehicle and to inject said liquid additive into an exhaust gas treatment system of said motor vehicle. 
     
     
         13 . A non-transitory computer readable medium having stored thereon instructions of a computer program for implementing the method according to  claim 1  when said instructions are executed by a processor.